Low-cost visual postural feedback with Wii balance board and Microsoft Kinect - a feasibility study

A posture training paradigm with visual biofeedback is presented for physical rehabilitation following posture disorders (e.g. Pusher Syndrome). The objectives of the current study were: to calculate centre of pressure (CoP) using Wii balance board, to calculate centre of mass (CoM) using Microsoft Kinect sensor, and conceptual design of visual postural-feedback paradigm so that the user can improve functional reach tasks. The algorithm for calculating the posture based on the line connecting CoP-CoM (i.e. the lean-line), which was validated offline with a convenient sampling of 10 elderly (>50 years) subjects, where the maximum angle of the lean-line (with horizontal, i.e. the lean-angle) was compared with the Berg Balance Score - a widely used measure to predict risk of falls in elderly - during maximum forward, sideways, and backward lean. Since both the CoP and CoM moved during the task, the line joining CoP-CoM was indicative of the posture. A high correlation was found between the maximum lean-angle and the Berg Balance Score, and therefore it was proposed as a viable biofeedback for posture training.